Null Hypothesis:There is no selection acting on the polymorphism of the Jelly babies and variation occurs due to genetic drift and gene flow. Alternative Hypothesis: There is significant selection acting on the polymorphism of the Jelly babies and some variation in the jelly babies is due to gene flow and genetic drift. If we accept the Alternative hypothesis, then selection plays a greater role compared to genetic drift and gene flow on the polymorphism of the Jelly babies E.g. there would be a higher frequency of certain coloured jelly babies in the shrub area compared to the grassland area and vice versa, so there may be darker coloured jelly babies in the shrub area and lighter coloured jelly babies in the grassland area. This is sort of pattern would be seen as a specific traits may be advantages in each habitat. However if we reject the alternative hypothesis and accept our Null hypothesis then the polymorphism of the jelly babies is due to genetic drift and gene flow and no selection is acting on the them. This would mean that there would be no clear correlation in the results when collecting from each habitat, therefore one sample collected from one area may not be similar to another sample collected from the same habitat. E.g. if we collect samples from the shrub area they may show different phenotypic ratios compared to the second and third samples collected from the other shrub areas. If genetic drift has a predominant effect on the phenotypic ratios then each polymorphism could appear in higher ratio at random in samples from the same environment. If gene flow has a predominant effect then the ratios would be relatively even across all the samples.
Method
As a group we have decided to conduct horizontal line transects at a higher altitude, thus controlling altitude as a variable. The samples would be taken from the shrub habitat and the grassland habitat, the distance between each samples from the shrub to grassland would be 20 meters to ensure that the populations are independent. There would be 3 samples from the shrub habitat and 3 from the grassland habitat. Before we start sampling we will make sure that all of us distinguish and categorise colours in line with one another. Advantage
By controlling the altitude we are ensuring that only the changes the independent variable, i.e. changes in habitat, are affecting the dependent variable, i.e. colour of jelly babies, thus increasing validity
Trying to ensure everyone distinguishes the colours in line with one another will ensure inter-observer reliability isn't low.
By only carrying out 6 samples we will ensure that we don't run out of time and that we collect enough information to compare the results and back up our hypothesis.
By collecting 3 samples from each habitat (shrub and grassland) ensures that we have enough population samples to minimise sampling error and increase reliability.
Collecting 3 samples from each habitat would enable us to compare the results and determine whether selection is playing a role or not. For example if A,C and E would all show that a certain phenotype(s) are predominant in this habitat we could assume that selection is playing a role, we could then further compare these results with that of the 3 sample collected from the shrub area, B,D and F if these show different patterns to A,C and E we could assume that the certain phenotype(s) observed in A,C and E are not advantages in the shrub area, again backing up that selection is playing a role. If this wasn't the case and there was no significant correlation between the samples collected for each habitat then we could assume selection is not playing a role and all variations observed are due to genetic drift and gene flow.
Weakness
By restricting ourselves to a certain altitude we may miss very important differences in the habitats at each altitude.
Time restrictions mean that we can only sample six areas, providing us with small sample size which means that our results may not be reliable and cannot be generalised. The study would benefit from pairing with another group following the same sampling strategy to increase the number of samples.
Inter-observer reliability may still be low and difficulty distinguishing colours may lower validity.
Distinguishing between Genetic drift, Selection and Gene flow Selection- if it is playing a role, then similar traits should appear in the 3 sample of one habitat (e.g. shrub) that is significantly different from other habitat Genetic drift- If it is playing a role, then different traits would appear in the 3 samples of the one habitat (e.g. Grassland) as they are independent to each other and frequencies may have changed due to random events. Gene flow- if it is playing a role, then there would be similar traits present in both shrub and grassland areas which as close to each other.
Null Hypothesis: There is no selection acting on the polymorphism of the Jelly babies and variation occurs due to genetic drift and gene flow.
Alternative Hypothesis: There is significant selection acting on the polymorphism of the Jelly babies and some variation in the jelly babies is due to gene flow and genetic drift.
If we accept the Alternative hypothesis, then selection plays a greater role compared to genetic drift and gene flow on the polymorphism of the Jelly babies E.g. there would be a higher frequency of certain coloured jelly babies in the shrub area compared to the grassland area and vice versa, so there may be darker coloured jelly babies in the shrub area and lighter coloured jelly babies in the grassland area. This is sort of pattern would be seen as a specific traits may be advantages in each habitat.
However if we reject the alternative hypothesis and accept our Null hypothesis then the polymorphism of the jelly babies is due to genetic drift and gene flow and no selection is acting on the them. This would mean that there would be no clear correlation in the results when collecting from each habitat, therefore one sample collected from one area may not be similar to another sample collected from the same habitat. E.g. if we collect samples from the shrub area they may show different phenotypic ratios compared to the second and third samples collected from the other shrub areas. If genetic drift has a predominant effect on the phenotypic ratios then each polymorphism could appear in higher ratio at random in samples from the same environment. If gene flow has a predominant effect then the ratios would be relatively even across all the samples.
As a group we have decided to conduct horizontal line transects at a higher altitude, thus controlling altitude as a variable. The samples would be taken from the shrub habitat and the grassland habitat, the distance between each samples from the shrub to grassland would be 20 meters to ensure that the populations are independent. There would be 3 samples from the shrub habitat and 3 from the grassland habitat. Before we start sampling we will make sure that all of us distinguish and categorise colours in line with one another.
Advantage
- By controlling the altitude we are ensuring that only the changes the independent variable, i.e. changes in habitat, are affecting the dependent variable, i.e. colour of jelly babies, thus increasing validity
- Trying to ensure everyone distinguishes the colours in line with one another will ensure inter-observer reliability isn't low.
- By only carrying out 6 samples we will ensure that we don't run out of time and that we collect enough information to compare the results and back up our hypothesis.
- By collecting 3 samples from each habitat (shrub and grassland) ensures that we have enough population samples to minimise sampling error and increase reliability.
- Collecting 3 samples from each habitat would enable us to compare the results and determine whether selection is playing a role or not. For example if A,C and E would all show that a certain phenotype(s) are predominant in this habitat we could assume that selection is playing a role, we could then further compare these results with that of the 3 sample collected from the shrub area, B,D and F if these show different patterns to A,C and E we could assume that the certain phenotype(s) observed in A,C and E are not advantages in the shrub area, again backing up that selection is playing a role. If this wasn't the case and there was no significant correlation between the samples collected for each habitat then we could assume selection is not playing a role and all variations observed are due to genetic drift and gene flow.
WeaknessDistinguishing between Genetic drift, Selection and Gene flow
Selection- if it is playing a role, then similar traits should appear in the 3 sample of one habitat (e.g. shrub) that is significantly different from other habitat
Genetic drift- If it is playing a role, then different traits would appear in the 3 samples of the one habitat (e.g. Grassland) as they are independent to each other and frequencies may have changed due to random events.
Gene flow- if it is playing a role, then there would be similar traits present in both shrub and grassland areas which as close to each other.